1. Field of the Invention
The present invention relates to focusing optics technologies, and more particularly to a focus-adjustable device and a system thereof, in which the focus of the focus-adjustable device and the system can be changed by way of filling with a fluid having a specific refractive index.
2. Description of the Prior Art
Optics lens are widely applied in various optoelectronic equipment, for example, illumination equipment and solar power equipment. In traditional solar power equipment, some basic lens such as convex, concave or prism are used for focusing sunlight in order to increase the photoelectric conversion efficiency of the solar power equipment. Nowadays, the miniaturization of the solar power equipment is demanded for facilitating the solar power equipment able to be popularly used. For thinning the thickness of the light-focusing lens in the solar power equipment, the conventional technology is to directly make the light-focusing lens thinner, and then applied the thinned light-focusing lens in the solar power equipment. However, the thinned light-focusing lens commonly includes an un-adjustable focus, and that is the primary drawback of the thinned light-focusing lens.
Accordingly, the optics device manufacturer makes studies and then develops an improved lens called Fresnel lens. Please refer to FIG. 1, which illustrates a schematic manufacture-processing diagram of a conventional Fresnel lens. Moreover, the top view of the conventional Fresnel lens is shown in FIG. 2. As shown in FIG. 1(a), FIG. 1(b) and FIG. 2, a Fresnel lens 1′ can be fabricated after making a plurality of concentric grooves 21′ on the convex surface of a convex lens 2′. To see the concentric grooves 21′ from one side of the Fresnel lens 1′, the concentric grooves 21′ are symmetric and take the center of the Fresnel lens 1′ as their symmetric center.
Continuously, the side view of the Fresnel lens 1′ is shown in FIG. 3. As shown in FIG. 3, when a light illuminates on one surface of the Fresnel lens 1′ without forming with the concentric grooves 21′, the light would pass through the Fresnel lens 1′ and be deflected by the concentric grooves 21′ formed on the other surface of the Fresnel lens 1′, therefore the light is focused on a focus point distancing from the surface of the Fresnel lens 1′ formed with the concentric grooves 21′. Comparing to the traditional convex lens, Fresnel lens 1′ shows the advantages of light weight, thinner thickness, shorter focus, lower price, and having non-convex surface; so that, the Fresnel lens 1′ is widely applied in the miniaturized solar power equipment by replacing the traditional convex lens.
However, when the solar power equipment is operated, it needs to control the sunlight to be largely collected through the optics lens during a light collection interval, and then the collected sunlight would be transformed into electric power by transforming modules; however, in others interval, it needs to make the sunlight pass through the optics lens unfocusedly, wherein the words of “make the sunlight pass through the optics lens unfocusedly” means that the optics lens which the sunlight passes through cannot concentrate the sunlight to a specific focus point distancing from the rear surface of the optics lens. Thus, for above descriptions, it is able to know that the Fresnel lens 1′ of FIG. 2 still cannot meet the operation requirement of the solar power equipment because the Fresnel lens 1′ including an un-adjustable focus and the sunlight would surely be concentrated at a focus point when passing through the Fresnel lens 1′.
Thus, through above descriptions, it is able to know that conventional optics lens and the Fresnel lens still includes drawbacks and shortcomings, so that the inventor of the present application has made great efforts to make inventive research thereon and eventually provided a focus-adjustable device and a system thereof.